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Editor-In-Chief: C. Michael Gibson, M.S., M.D.; Associate Editor(s)-in-Chief:Abiodun Akanmode



Cough can be classified based on duration i.e

  • Acute cough: This type of cough usually presents with a duration of fewer than 3 weeks.
  • Sub Acute cough: Last between 3-8weeks.
  • Chronic Cough: Chronic cough usually presents for a duration greater than 8weeks.

Cough can also be classified based on sputum production i.e

  • Non-productive cough.
  • Productive cough.


The act of cough is a vital one that occurs through the stimulation of the cough reflex which is a complex relex arc. The cough reflex arc is constituted by 3 main components ie

  • The Afferent pathway: This made up of sensory nerve fibers in the ciliated epithelium found in the upper airways. The afferent impulses are transmitted into the medulla.
  • The efferent pathway: cough impulses that is originated from the cough central travels via the vagus nerve,phrenic nerve, and spinal motor nerves to the diaphragm and abdominal wall muscles.
  • Central pathway: This is a central area located within the pons and brainstem. It coordinates the cough reflex arc.

The Afferent sensory nerves:There are 3 manjor classes of afferent sensory nerves,this classification is based on there conduction velocity(A-fiber, > 3 m/s; C-fiber, < 2 m/s),origin ,myelination,neurochemistry etc.

  • Rapidly adapting receptors (RARs)
  • Slowly adapting stretch receptors (SARs)
  • C-fibres.

The series of mechanical activities that take place during coughing is divided into 3 phases.


The common causes of cough are:

Less common causes of cough are:

Causes Examples
Drug use Abacavir, Abatacept, ABVD, ACE inhibitor, Acetylmorphone, Acyclovir, Adalimumab, Adefovir, Albuterol, Alefacept, Alfuzosin, Aliskiren, Amiodarone, Amlodipine and Benazepril, Amphotericin B, Anagrelide, Anastrozole, Artemether/lumefantrine, Atazanavir, Aztreonam, Benazepril, Bepridil, Bevacizumab, Bitolterol, Bortezomib, Brimonidine, Budesonide, Busulfan, Captopril, Carvedilol, Cetuximab, Cevimeline, Chlorambucil, Ciclesonide, Cladribine, Clobutinol, Clofarabine, Clofedanol, Co-trimoxazole, Conjugated estrogens, crofelemer, Cromolyn Sodium, Cytarabine, Dacarbazine, Dactinomycin, Darbepoetin Alfa, Denileukin diftitox, Desmopressin, Diborane,
Infectious disease Adenoviridae, Aphthovirus, Ascaris infection, Aspergillosis, Blastomycosis, Bordetella pertussis, Byssinosis, Chickenpox, Chlamydophila pneumonia, Cladosporium, CMV Pneumonitis, Coccidioidomycosis, Community-acquired pneumonia, Cryptococcosis, Fasciolosis, Filariasis, Gnathostomiasis, Histoplasmosis, Human ehrlichiosis, Infectious mononucleosis, Influenza, Lady Windermere syndrome, Lassa fever, Legionellosis, Measles, Melioidosis, Miliary tuberculosis, Mucor.
Genetic diseases Cystic fibrosis, Juvenile Myelomonocytic Leukemia (JMML)
Environmental agents Chronic beryllium disease (CBD), Hay fever, Low humidity, Occupational exposure of irritants Passive smoking, Sick building syndrome, Silicosis, Smoking.
Malignancies Cervical mass, Esophageal cancer, Kaposi's sarcoma, Laryngeal cancer, Lymphangitis carcinomatous, Mediastinal tumor, Mesothelioma, Papillomatosis, Thymoma.

Cough Differential Diagnosis

  • Acute Cough Diffrential Diagnosis.
Acute Cough
Viral Urti

  • Subacute cough Differential diagnosis.
Subacute Cough
Bacterial sinusitis
Postinfectious cough

  • Chronic cough Differential Diagnosis.
Chronic Cough
GERD,Tobacco use
Chronic diseases:CHF,Sarcoidosis,Cystic fibrosis etc
Asthma,Pharmacologic drug:ACEI,Beta Blockers


Associated symptoms such as fever, vomiting, night sweats, weight loss, sputum production and quantity, smoking history, drug use, etc help the clinician with making a list of plausible differential diagnoses.

Differentiating cough from other Diseases

Making a differential diagnosis when a patient presents with a cough can be challenging however the clinician should utilize other associated symptoms such as fever, vomiting, night sweats, weight loss, sputum production and quantity, smoking history, drug use and most importantly the duration of the cough to make a list of plausible differential diagnoses.

Cough epidemiology and demographics

Cough is the most common cause of visits to primary care doctors and pulmonologist, it accounts for about 40% of outpatient visits.

Risk Factors for cough

The risk factors for cough are closely linked with its various causes, however, certain factors such as smoking, seasonal allergies, and air pollution can increase a patients cough hypersensitivity.

Natural History, Complications and Prognosis